1. Field of the Invention
The present invention relates to a film for labels having an easy cutting property. More particularly, the present invention relates to a film for labels having a freely deformable property, and a high severability in cutting, which is excellent in severability at the time of die cutting in the process of production of the labels, in adaptability to labelling, and in accommodating property to a flexible vessel to which the label is attached.
2. Description of the Related Art
Labelling films have been used as adornment on the outer surfaces of containers and required to have the most basic characteristic, i.e., the severability into labels of various sizes and configurations when cutting with a die. In addition, there are marketed numerous flexible containers as well as hard ones so that they are also required to have a freely deformable property (referred to as accommodative property hereunder) accommodating to the configurations of the containers, particularly of flexible containers.
Japanese Patent KOKAI (Laid-open) No. Sho 61-107377 discloses a high severability film having a low Elmendorf tear strength suitable for cap labels as proposed therein. However, the tear strength of the film of this patent is too low for labels on flexible containers causing a problem that the labels tear when the containers are deformed.
U.S. Pat. No. 4,587,158 proposes a freely deformable label comprising polyethylene resins.
In order to accommodate the labels to flexible containers, polyethylene resins having an appropriately low rigidity have been heretofore preferred to be used. However, a lower rigidity causes problems that in the, step of affixing labels cut on a release sheet onto containers by an automated labelling machine, the labels are not successfully released from the release sheet or wrinkled making it impossible to, affix uniformly (such property of the labels is referred to as adhesive property hereunder). Particularly, films having a lower rigidity have a poor severability so that they can not be satisfactorily cut in a predetermined label form in the die cutting step (referred to as severability in die cutting hereunder) to inhibit stable supply of labels resulting in a lower productivity at a high loss.
The present inventors have made an intensive research to develop a film for labels having a good accommodative property to flexible containers, a good adhesive property and a satisfactory die cut severability to overcome the problems as described above, and as a result, have found that films having various performances preferred for labels can be attained by mixing a polypropylene resin and a polyethylene resin and allowing them to be present in a phase separate structure. The present invention is based on this findings.